One-way check valves are present in a variety of applications for which the flow of a liquid or a gas is intended to be essentially unidirectional. While it is easy to properly align and insert these valves into stainless steel or copper tubes, this is not the case when the valve is flexible and the tube is either a rigid or flexible plastic, and particularly when subsequent manipulative steps are performed on the workpiece. These operations may shift the initial position of the flexible valve to a skewed position, thereby permitting the backflow of liquid through the valve, and defeating the purpose of the valve. This is particularly true during overmolding operations as will be discussed below wherein the valve inside the tube is subject to a pressurized heated mold environment such as is present in overmolding applications.
It is well known to encapsulate components within a plastic molding die cavity by rigidly affixing such components to or through the walls of the cavity. It is also known to avoid the appearance of holding devices at the surface of the molded product by providing retractable holding devices which retract out of the molding cavity while the molding material is setting up. It is also possible for the holding devices to retract into the center of the molded product. Such prior art holding devices and techniques, however, do not hold the encapsulated component in a precisely defined position, and are therefore, of limited usefulness. In many applications, the encapsulated components must maintain precise positions relative to other encapsulated components or with respect to the exterior contours of the molded product.
The problem of precisely positioning encapsulated components within an injection molding cavity can be further complicated by two additional factors. If the component to be encapsulated is not rigid, the problem of holding it in a precise position is far more difficult. Furthermore, the dimensions of the molded product may be such that very little leeway exists for positioning the encapsulated component away from the surfaces of the mold.